forced inducution/5.0 gurus: please help
 

well its running. All gauges hooked up and all systems nominal. The a/f gauge is a little eradic but i heard that is to be expected. The only problem is the darn thing wont exceed 3 - 4 lbs of boost. When I floor it, there is a big hesitation, and when it passes 2750 rpms, it revs incredibly slowly, surges back and forth, and refuses to pass 4 lbs of boost. Under the hood, I feel a big gust of wind near the blower. The wind is so strong it blew some loose bolts in my garage around when I revved it. I can't find a leak, but i suppose this doesnt mean there is one.

My harmonic balancer is dirty and the timing is hard to read, i'm not sure i'm getting the timing right at all.

Could this be a timing issue or a leak, or something I havent thought of completely? Any ideas?

You should clean your motor, and check the timing, it may not be your problem, but timing is very important, especially with a forced car.

What size fuel pump do you have? You will need a 190 with a blower.

Do you have any other mods? Cam, intake, ect..?

Ian

Ok, 88COBRA, he needs a 255 which was discussed in another thread. ;)

Just to be clear, you don't happen to have an underdrive pulley on your crank, do you? I know a guy that left it on and was wondering why he was not building boost.

Ok just to be sure, all piping and clamps are secure? Are the vacuum lines secure and no leaks? What is your vacuum at idle? How is your blow-off valve hooked up? Forgetting not to plug in the blow-off valve will definately cause that problem. ( mine fell out the other day on the freeway )

I have a fuel pump that came with the kit. Together with the stock pump it is supposed to make around 255 lph. However, I dont see how fuel pump affects boost. My vacuum sits between 15 - 20 in. mercury at idle. Under quick punch the vacuum jumps to 0 but has alot of trouble building boost after that. The surge valve is vacuum activated (IE it is closed normally, but opens under vacuum.) and seems to be working properly, although I am not sure. It is hooked up to the Fuel Pressure Regulator. Does all this seem good to ya'll?

Why does he need a 255? I only plan on installing a 190 for my setup. 255 seems like allot.

Do you have a large blower?

The rest sounds good to me.....

Ian

88cobra,
Your putting a novi on your car and you plan on a 190lph:o, you should get a Walbro WSS340 255lph HV.

93gtdin,

Sounds like you have a air leak coming from the discharge tube(blower to TB). Loosen up all the clamps and make sure its on there properly.

Also did you use a torque wrench to tighten the blower belt? You don't have too but its more accurate, obviously.

Yes Ian you will need a 255lph.

93GTDIN I know this is off subject, but just adding an inline isn't as good as having a 255lph intank and the inline (Trex for example).

But back on track, did you install a blow off valve? If so, again make sure its properly connected and functioning properly.

well, i figured out that I didnt have the belt tightened down nearly enough. ATI told me look for black dust as a sign of belt slippage, and sure enough, black dust-o-plenty.

Another problem i'm havin is that it looks like i'm getting about 8 -10 mpg. This really upsets me seeing as how I used to get 18 - 20. Also, I havent gotten on the car at all, i've basically kept it below 2500 rpms cause it's been really wet. any particular reason this is happening?